The present invention relates to techniques for coupling tubular conduits to ports in a valve or block and particularly relates to connecting high pressure refrigerant tubes to expansion valves or connector blocks in the refrigerant circulation system. Quick connect couplings are employed to facilitate the assembly of automotive air conditioning systems in mass production as a means of reducing the amount of labor required to assemble the system components prior to charging with refrigerant. In such systems, the refrigerant is typically subjected to a relatively high pressure on the order of 350 psi (2400 kPa) upon discharge from the refrigerant compressor; and, thus the conduit fittings must seal such pressures and retain long term seal integrity over the service life of the automotive vehicle.
Heretofore, it has been the practice in assembling tubular conduits to ports in a valve or block to provide an annular seal in the port for sealing about the neck or end of the tube when inserted therein and to provide an annular convolution or bulge in the wall of the tube to provide a surface on the tube for mechanical retention on the block or valve. Typically, in such tubular connections, a retainer plate having an apertured or bifurcated end has the aperture or bifurcated portion disposed against the face of the bulge or convolution; and, the retainer is mechanically secured to the valve or block by suitable means such as metal deformation, localized staking, or threaded fasteners. Another technique employed for retaining the tube is to orbitally stake the material of the block or valve about the port over the convolution of the tube. Either of the aforesaid techniques for attaching a tubular conduit to a valve or block requires complicated attachment or fabrication operations at assembly and therefor have proven prohibitively costly for tubular conduit connections in mass production assembly of automotive air conditioning systems. Thus it has been desired to provide a way or means of quick connecting tubular conduits onto a junction block or valve for use with relatively high pressures in a manner which provides reliable low cost assembly in mass production and which requires no tools or installation of fasteners at the time the connection is made at assembly.